Fair Value Measurement - Estimated Fair Values of Financial Instruments that are Reported at Amortized Cost in Consolidated Balance Sheets (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Financial assets:
Cash and due from banks	$ 92,816,000	$ 119,781,000
Cash at Federal Reserve and other banks	183,691,000	107,752,000
Securities held to maturity	375,606,000	444,936,000
Restricted equity securities	0	0
Financial liabilities:
Other borrowings	18,454,000	15,839,000
Junior subordinated debt	57,232,000	57,042,000
Level 3 \| Overdraft privilege commitments
Off-balance sheet:
Contract amount, Off-balance sheet	110,402,000	111,956,000
Level 3 \| Standby letters of credit
Off-balance sheet:
Contract amount, Off-balance sheet	12,014,000	11,346,000
Level 3 \| Commitments
Off-balance sheet:
Contract amount, Off-balance sheet	1,309,326,000	1,192,054,000
Fair Value \| Level 1
Financial assets:
Cash and due from banks	92,816,000	119,781,000
Cash at Federal Reserve and other banks	183,691,000	107,752,000
Fair Value \| Level 2
Financial assets:
Securities held to maturity	381,525,000	437,370,000
Financial liabilities:
Deposits	5,365,921,000	5,362,173,000
Other borrowings	18,454,000	15,839,000
Fair Value \| Level 3
Financial assets:
Loans, net	4,263,064,000	4,006,986,000
Financial liabilities:
Junior subordinated debt	56,297,000	62,610,000
Fair Value \| Level 3 \| Overdraft privilege commitments
Off-balance sheet:
Fair value, Off-balance sheet	1,104,000	1,120,000
Fair Value \| Level 3 \| Standby letters of credit
Off-balance sheet:
Fair value, Off-balance sheet	120,000	113,000
Fair Value \| Level 3 \| Commitments
Off-balance sheet:
Fair value, Off-balance sheet	13,093,000	11,921,000
Carrying Amount \| Level 1
Financial assets:
Cash and due from banks	92,816,000	119,781,000
Cash at Federal Reserve and other banks	183,691,000	107,752,000
Carrying Amount \| Level 2
Financial assets:
Securities held to maturity	375,606,000	444,936,000
Restricted equity securities	17,250,000	17,250,000
Financial liabilities:
Deposits	5,366,994,000	5,366,466,000
Other borrowings	18,454,000	15,839,000
Carrying Amount \| Level 3
Financial assets:
Loans, net	4,276,750,000	3,989,432,000
Financial liabilities:
Junior subordinated debt	$ 57,232,000	$ 57,042,000

Cash at federal reserve and other banks.

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Off balance sheet.

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For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Amount of restricted investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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The fair value of financial liabilities, which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition.

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The face amount of financial liabilities, which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition.

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Amount of investment in debt security measured at amortized cost (held-to-maturity).

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Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

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